Modular electrical bus system with built in ground circuit

Abstract

A modular electrical bus system has a grounding circuit through a plurality of modular I/O units with each unit being both electrically and mechanically connectable together via a bridge member connecting adjacent units and the main communication module. The bridge member and modular I/O units are grounded together with a ground circuit that extends within both components.

1. A modular electrical bus system for a valve manifold comprising:
 a main communication module; 
 a plurality of modular I/O units each having a plurality of I/O fittings; 
 said I/O units being both electrically and mechanically connected together and connected to the main communication module; 
 a bridge member connecting adjacent modular I/O units together; 
 said modular I/O units each having a housing with opposite sides that can be juxtaposed adjacent each other; and said sides having recessed font faces with respect to a main face of said housing; 
 said opposite sides having electrical fittings that are interposed between two main faces of two adjacent modular I/O units; 
 said opposite sides also having ground contacts electrically connected to each other; 
 said bridge member fitting in a gap formed in front of the recessed front faces between the main faces of two adjacent modular I/O units for mechanically connecting and affixing to both of said adjacent modular I/O units; and 
 said bridge member having an electrically conductive strap mounted therein which can be in electrical contact with said ground contacts of the two adjacent modular units. 
 
     
     
       2. A modular electrical bus system as defined in  claim 1  further comprising:
 said bridge member having complementary electrical fittings for connecting to the electrical fitting of said adjacent modular I/O units to electrically connect the adjacent modular I/O units. 
 
     
     
       3. A modular electrical bus system as defined in  claim 2  further comprising:
 said conductive strap entrapped within the body of said bridge member and having annular exposed shoulders mounted in counterbores in said body; and 
 said annular exposed shoulders having a respective aperture therein aligned with a respective aperture within the body of said bridge member for receiving and contacting a fastener that engages the ground contacts in the adjacent modular I/O units. 
 
     
     
       4. A modular electrical bus system as defined in  claim 3  further comprising:
 each modular I/O unit having its ground contacts in engagement to a trace on an internal board mounted within a housing and with the board extending across the housing of said modular I/O unit. 
 
     
     
       5. A modular electrical bus system as defined in  claim 4  further comprising:
 said ground contacts of said modular I/O unit being a conductive bushing which receives said fastener at one end that mounts said bridge member and a fastener that mounts said board to said housing at an opposite end. 
 
     
     
       6. A modular electrical bus system as defined in  claim 5  further comprising:
 said conductive bushing having blind threaded holes at each end thereof and sealingly fitted in said housing of said modular I/O unit. 
 
     
     
       7. A modular electrical bus system as defined in  claim 5  further comprising:
 said housing of each modular I/O unit having said main front face and a first electrical connection proximate to one side and a second electrical connection proximate another side; 
 a plurality of I/O fittings on the main front face of said housing; 
 said one side of said housing shaped to fitted adjacent said other side of an adjacent I/O module and to receive said bridge member; 
 said first electrical connector at a first front face section that is recessed from said main front face; 
 said second electrical connector at a second front face section that is recessed from said main front face; 
 said first and second front face sections being complementarily shaped to interlock adjacent modules together in a mounting plane; 
 said first and second front face sections having complementary dove tail shapes to interlock together; 
 said front face section at said one side of said housing and said second front face section at the other side of said housing being aligned at the same distance from said main front face; 
 said first electrical connection being laterally aligned with said second electrical connection of an adjacent module when said adjacent modules are connected together; and 
 said conductive bushings also being aligned with each other to receive fasteners contacting adjacent modular I/O units and said bridge member. 
 
     
     
       8. A modular electrical bus system as defined in  claim 2  further comprising:
 said bridge member having fasteners that attach to two adjacent I/O modules electrically, mechanically and with a grounding circuit continuously therethrough. 
 
     
     
       9. An electrical bus assembly comprising:
 a main communication module; 
 a bank of modular I/O units mounted to the side of the main communication module and adjacent each other; 
 each modular I/O unit having an electrical fitting in proximity to each side thereof; 
 a bridge member spanning and connecting two adjacent modular I/O units; 
 said bridge member having complementary electrical fittings for engaging the electrical fittings of two adjacent I/O units; 
 said modular I/O units being mountable to a mounting base; 
 said bridge member mechanically connecting said adjacent modular I/O units together such that when said bridge members are disengaged from one modular I/O unit, said one modular I/O unit is removable from said mounting base and said bank of modular I/O units without removing adjacent left and right modular I/O units; 
 each modular I/O unit enclosing an electronic board therein and being distributable to a remote location and electrically connectable to the bank and main communications module; 
 said electronic board having a ground trace extending thereacross that have opposite ends in contact electrically to each other; and 
 said bridge member having electrically conductive contacts mounted therein which are in electrical contact with the ground traces of two adjacent modular units. 
 
     
     
       10. A modular electrical bus system as defined in  claim 9  further comprising:
 said traces on said electronic board being in contact with a fastener; said fastener being in contact with conductive bushing at one end; the bushing has a second end which receives a second fastener that mounts said bridge member; 
 said first electrical connection being laterally aligned with said second electrical connection of an adjacent I/O module when said adjacent modules are connected together; and 
 said conductive bushings also being aligned with each other to receive said second fasteners contacting adjacent modular I/O units and said bridge member. 
 
     
     
       11. A modular electrical bus system as defined in  claim 10  further comprising:
 said conductive bushing having blind holes at each end thereof and sealingly fitted in said housing of said modular I/O unit. 
 
     
     
       12. A modular electrical bus system for a valve manifold comprising:
 a main communication module connected to a plurality of manifold valves; 
 a plurality of modular I/O units each having a plurality of I/O fittings accessible from an exterior of a housing for said I/O units; 
 said I/O units being both electrically and mechanically connected together; and 
 a grounding circuit extending through said plurality of said housings for said I/O units with electrical contacts for electrically connecting the grounding circuit together through said plurality of said housings. 
 
     
     
       13. A modular electrical bus system as defined in  claim 12  further comprising:
 said housing substantially made from a non-conductive material; and 
 said contacts include a bridge member that connect two housings together. 
 
     
     
       14. A bridge member for an electronic bus system comprising:
 a body made from an electrically non-conductive material; 
 electrical connectors for connecting electrical circuits between adjacent I/O modules of said bus system; 
 an internal conductive material extending between two counterbores in said body and having an exposed section in said counterbore; and 
 an aperture extending from each counterbore for receiving an electrically conductive fastener that can be in contact with the internal conductive material and to ground traces in adjacent I/O modules to form a complete ground circuit extending through the I/O modules and through said bridge member. 
 
     
     
       15. A bridge member as defined in  claim 14  further comprising:
 said body being molded substantially about said conductive material; and 
 said conductive material being an electrically conductive strap having at least two annular exposed sections mounted about the respective apertures in said counterbores.